J Agric Food Chem. 2021 Feb 17 ;69(6):1816-1830. Epub 2021 Jan 6. PMID: 33406828
Metabolite Profile of Cucurbitane-Type Triterpenoids of Bitter Melon (Fruit of) and Their Inhibitory Activity against Protein Tyrosine Phosphatases Relevant to Insulin Resistance.
Qualitative analysis of cucurbitane-type triterpenoids of bitter melon (fruit ofL.) using ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry revealed 27 promising cucurbitane-type triterpenoids, and LC/MS-guided chemical analysis offruit extract led to the isolation and structural characterization of 22 cucurbitane-type triterpenoids (), including 8 new cucurbitane-type triterpenoidal saponins, yeojoosides A-H (). The structures of the new compounds () were elucidated by spectroscopic methods, including 1D and 2D NMR and high-resolution electrospray ionization mass spectrometry. Their absolute configurations were assigned by quantum chemical electronic circular dichroism calculations, chemical reactions, and DP4+ analysis using gauge-including atomic orbital NMR chemical shift calculations. All isolated compounds () were examined for inhibitory activity against protein tyrosine phosphatases relevant to insulin resistance. Nine compounds (,,,,,,,, and) showed selective inhibitory effects of over 70% against PTPN2. The present results suggested that these compounds would be potential antidiabetic agents.